Nailing gun carriage

ABSTRACT

A carriage for a portable nailing gun is supportively mounted on a pair of journaled wheels at the rear thereof and on a single wheel at the front thereof. The rear wheels are of relatively large diameter compared to the front wheel. The carriage includes a frame with a rearwardly and upwardly extending handle. The forward portion of the frame carries a pivotable bracket on which is removably mounted a portable nailing gun. The nailing gun is pneumatically powered and is actuated through an adjustable camming mechanism associated with one of the rear wheels. An independent hand actuating mechanism is located on the handle so that, in addition to the actuation by moving the carriage, nails can be driven independently at desired locations.

United States Patent [19] Downing 1 Mar. 12, 1974 NAILING GUN CARRIAGE Hugh N. Downing, 5012-100th St. NE, Marysville, Wash. 98270 [22] Filed: Apr. 5, 1972 [21] Appl. No.: 241,124

[76] Inventor:

[52] US. Cl. 227/8, 227/111 [51] Int. Cl 1327f 7/02 [58] Field of Search 227/1, 5, 7, 8,110, 111

[56] References Cited UNITED STATES PATENTS 2,915,754 12/1959 Wandel 227/111 X 3,173,593 3/1965 Elliott 227/111 3,186,616

6/1965 Weems 227/8 Primary Examiner-Granville Y. Custer, Jr. Attorney, Agent, or Firm-Christensen, OConnor, Garrison 8L Havelka 4 [5 7] ABSTRACT A carriage for a portable nailing gun is supportively mounted on a pair of joumaled wheels at the rear thereof and on a single wheel at the front thereof. The rear wheels are of relatively large diameter compared to the front wheel. The carriage includes a frame with a rearwardly and upwardly extending handle. The forward portion of the frame carries a pivotable bracket on which is removably mounted a portable nailing gun. The nailing gun is pneumatically powered and is actuated through an adjustable camming mechanism associated with one of the rear wheels. An independent hand actuating mechanism is located on the handle so that, in addition to the actuation by moving the carriage, nails can be driven independently at desired locations.

27 Ciairns, 3 Drawing Figures NAILING GUN CARRIAGE BACKGROUND OF THE INVENTION This invention relates to nailing guns and more particularly to a carriage on which a portable nailing gun can be removably mounted.

Many nailing guns exist in the prior art. Most of the nailing guns are of the portable handheld type. Various examples of such nailing guns are illustrated in U.S. Pat. Nos. 3,253,760, 3,190,187, 3,094,900, 3,081,742, 3,043,272, 2,979,725 and 2,944,522. Such nailing guns acceptable for large volume commercial work are relatively heavy. When nailing floor sheeting to floor joists, the operator of such guns must bend over to operate the gun. Such work can be very tiresome and requires rest periods. Thus to efficiently utilize such a nailing gun in large volume production, more than one operator must be employed or valuable production time is lost.

The portable nailing guns of the type disclosed in the above-mentioned patents are pneumatically operated from a remote source of air pressure or the like. Other nailing guns are available which are electrically powered. The present invention applies to a carriage for both types of nailing guns.

Most nailing guns are actuated by depressing a trigger conveniently located on one of the handles of a nailing gun. Most such nailing guns also include a safety trigger mechanism which is actuated when the nail delivery tube of the nailing guns is situated near the surface to be nailed. The safety trigger prevents inadvertent flring of the gun when no surface is adjacent the delivery tube to receive the nail. Generally, the safety trigger includes a sleeve surrounding the nail delivery tube or a pin extending outwardly beyond the nail delivery tube. As the tube is engaged with a floor, the safety trigger mechanism is moved to activate the handactuated trigger of the gun.

It is an object of the present invention to provide a carriage on which a portable nailing gun can be mounted. It is a further object of the present invention to provide a carriage on which a portable, pneumatically powered, nailing gun can be mounted. It is a further object of the present invention to provide actua tion of the nailing gun responsive to movement of the carriage along a surface to be nailed. It is a further object of the present invention to provide means for actuating the nailing gun independent of the movement responsive actuating means.

It is a further object of the present invention to provide a nailing gun carriage and portable nailing gun combination which will provide more efficient utilization of manpower and equipment for relatively large volume nailing operations. It is a further object of the present invention to provide a nailing gun carriage which will eliminate much of the physical exertion required by the operator thereof. It is a further object of the present invention to provide a nailing carriage which is easy and simple to operate. It is a further object of the present invention to provide a nailing carriage which is capable of carrying a nail hopper to supply the nailing gun. It is a further object of the present invention to provide the feature of easy removability of the nailing gun from the carriage so that the nailing gun can be utilized for handheld operations, such as wallsheathing nailing and the like. It is a further object of the present invention to provide a nailing gun mounting on a carriage which has provision for allowing recoil of the nailing gun at the time of firing. It is a further object of the present invention to provide a nailing gun mounting on a carriage which effectively utilizes the safety trigger mechanism present on most commercially available portable nailing guns. It is a further object of the present invention to provide a nailing gun carriage structure by which the nailing gun can easily be lifted from the floor and rendered inoperative.

SUMMARY OF THE INVENTION The present invention therefore provides a carriage for use with a portable nailing gun having an actuating trigger thereon comprising a frame carrying a first pair of supporting wheels journaled thereon and at least a third supporting wheel journaled thereon, the frame including a handle mounted thereon and having a cross bar means at the other end thereof for grasping by an operator, a bracket means removably connectable to a portable nailing gun, the bracket means mounted for movement on the frame to recoil when the gun recoils and to return the gun to a ready position after recoil, actuating means mounted on the carriage for operatively causing the gun to discharge a nail responsive to a signal from a relay means located elsewhere on the carriage.

BRIEF DESCRIPTION OF THE DRAWINGS A better understanding of the present invention will be acquired by reading the ensuing specification in conjunction with the accompanying drawings wherein:

FIG. 1 is an isometric view showing the nailing gun carriage of the present invention;

FIG. 2 is an elevation view of the nailing gun carriage; and

FIG. 3 is a detail of the shoe of the present invention as mounted on the safety trigger mechanism of a portable nailing gun.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to FIG. 1 the carriage of the present invention, generally designated 10, has a primary structural frame 12 substantially triangular in shape. A pair of handles 14 composed of hollow bar stock are connected to the rearward portion of the frame 12. A cross bar 16 attached to the upper end of the handles 14. The cross bar 16 extends laterally beyond the upper ends of the handles 14 so that the protruding ends of the cross bar 16 can be grasped by an operator. A rear axle 18 is journaled on a pair of structural flanges 20 mounted on the frame 12. A pair of large diameter wheels 22, preferably about 15 A inches in diameter (i.e., 48 inches circumference), are mounted on the ends of the axle 18. A downwardly extending vertically adjustable axle carrier 24 is connected at the forward end of the frame 12. A small diameter wheel 26 is journaled on axle 28 in turn connected to the axle carrier 24.

A nailing gun bracket generally designated 30 is also attached to the forward end of the frame 12. Bracket arm 32 is pivotally connected by bolt 34 to flange 36. Flange 36 is firmly connected to one of the members of frame 12. Attached to the upper end of bracket arm 32 is a laterally extending flange 35. A portable nailing gun 37 is removably connected to the laterally extending flange 35 by four fasteners 38. The laterally extend- 3 ing flange 35 positions the nailing gun 37 in outrigger fashion outboard of the frame 112, to facilitate nailing along wall structures and the like. The pneumatically powered nailing gun 37 of the type illustrated is wellknown in the prior art. Exemplary guns are described in the above referenced patents.

A spring retention flange 40 is also attached to the frame l2. A coil spring 42 is interconnected in tension between retention flange 40 and the upper portion of arm 32. The coil spring 42 counterbalances the weight of the nailing gun 37 on the bracket 30 so that smooth recoil and operation of the nailing gun is achieved. The spring also permits smooth upward and downward movement of the gun during passage over nailing surface irregularities but prevents excessive downward movement of the gun when the front wheel of the carriage is raised.

Nailing gun 37 is preferably of the type which includes a safety actuating trigger. in the embodiment shown a safety trigger arm 46 is mounted for vertical reciprocating movement. As shown in FIG; l the actuating arm is carried on a pair of removable fasteners 54 retaining the arm 46 through associated slots. At its upper throw, arm 46 will arm the nailing gun by opening a pneumatic valve within the gun 37. At its downward throw arm 46 will close the valve deactivating the nailing gun 37.

The safety trigger arm 46 (FlGS. l and 3) is connected to a safety sleeve 50 surrounding the nail delivery tube and mounted for vertical sliding movement on the delivery tube 44. in accordance with this invention, a shoe 48 is removably connected to safety sleeve 50 by means of a set screw 52. Shoe 48 serves to prevent the safety sleeve Stl from catching on irregularities on the surface to be nailed.

The nailing gun shown in the drawings includes an automatic feeder 56 which can be loaded with prepackaged nail clips containing twenty or more nails per clip. Alternatively, as shown in ghost outline, a nail hopper 58 can be mounted on the frame l2 and handles 14. The nail hopper 56 is designed to feed nails, head up, to the automatic feeder 56. Such hoppers are known in the prior art. An important advantage of this invention is to include such a hopper 58 so that bulk nails (which are less expensive than the prepackaged clips) can be used and so that the operator need not reload the nailing gun as frequently as when the clips are used.

Referring now to both FlGS. l and 2 an adapter flange 60 is mounted by a suitable fastener on the body of the nailing gun 37 adjacent the main actuating trigger 62. Flange 60 carries a pneumatic cylinder 64 having its piston rod 66 in contact with the actuating trigger 62. The cylinder 64 is pressurized by air fed through conduits 68 and 70 connected to the bottom of the cylinder 64. Cylinder 64 is designed to raise the piston rod 66, thus moving trigger 62 to actuate the gun 37. At the upper end of the stroke of piston rod 66 the pneumatic pressure in cylinder 64 is automatically relieved thus allowing the rod 66 toreturn to its normally down position. Thus, the piston rod has a servo function with respect to the trigger 62.

Pneumatic pressure is fed to the nailing gun 37 via a main conduit 72 which connects to the nailing gun by a quick-connect coupling 76. The main supply conduit 72 is attached by brackets 78 to the handles 14. The first portion of the main conduit 76 is also attached to a manifold 80. Manifold 30 is in turn connected to a feed conduit 82 which receives pneumatic pressure from a source 84.

Manifold in addition to supplying conduit 72 feeds a first relay conduit 86. Relay conduit 86 travels downthe center of one of the handles l4 and connects with pneumatic relay valve 88. Relay valve 88 is mounted on a flange 90 connected to frame l2. An actuating arm 92, also mounted on the flange 90, opens the normally closed valve 88 to admit air to conduit 68 at intervals when the valve 88 is open. Thus when actuating arm 92 opens valve 88, pneumatic pressure is supplied through conduit 68 to pneumatic cylinder 64, which in turn actuates the nailing gun trigger 62.

A hub 94, attached to wheel 22 to rotate with wheel 22, carries a plurality of rollercams 96. As the wheel 22 rotates, hub 94 will cause roller earns 96 to circumscribe a path in which a follower roller 98 is located. The follower roller 98 is connected to the valve actuating arm 92. Thus, for every revolution of the wheel 22 the valve 88 and thus the nailing gun 37 will be actuated four times. Additional holes 100 are provided at predetermined spaced intervals on the hub 94 so that spare roller cams 102, conveniently stored on the hub 94, can be inserted to decrease the nail spacing. In a similar manner by removing certain of the roller cams 96 the nail spacing can be increased.

lt is periodically desirable and/or necessary to add extra nails to the surface being nailed. For example, when approaching a wall or the edge of a floor surface, it may be desirable to place one or two extra nails in the flooring to secure the edge of theflooring to the joists. The carriage of the present invention provides this function through a second relay valve 104 mounted on the handle 14 near the cross bar 16. Valve 104 is handactuatable by button 106, easily accessible to the operator of the carriage 10. The input to valve 104 is interconnected with the manifold 80 by conduit 108. The outlet port of valve 104 is connected to the cylinder 64 via conduit '70. Thus when the valve button 106 is depressed pneumatic pressure is admitted to the conduit 70 which in turn admits pressure to the cylinder 64, actuating the nailing gun 37. Thus additional nails can be added as desired.

As mentioned above, the preferred diameter of the rear wheels 22 is around 15% inches. This is desired not only for easy rolling but to facilitate the camming action provided by the hub 94 and roller earns 96. With a larger diameter wheel, it is of course possible to have greater variance in the spacing of roller earns 96 and thus the spacing of nails being placed by the nailing gun 37.

When it is desired to cease operation of the nailing gun 37, but not disconnect the carriage from the pneumatic source the entire carriage is tilted backwardly about the axle 18. Thus the nailing gun 37 is raised above the surface to be nailed, downward movement of the gun being limited by spring 42 as described previously. As the nailing gun 37 is raised above the surface to be nailed, the shoe 48, ring 50 and safety trigger arm 46 fall to their downward position. Thus the'nailing gun is automatically deactivated when the carriage 10 is tilted backwardly. 1

Although the present invention has been described in relation to a preferred embodiment it is understood that various changes, alterations and substitutions of equivalents can be made without departing from the original concept. For example, electrically actuated gun and relays can be substituted for the pneumatic gun and relays described. It is therefore intended that the invention be limited only by the definition contained in the appended claims.

What is claimed is:

l. A nailing gun carriage comprising:

a frame having forward and rearward ends, said frame including a handle affixed to the rearward end thereof,

a pair of wheels journaled adjacent the rearward end of said frame,

at least a third wheel journaled adjacent the forward end of said frame,

bracket means mounted for upward and downward movement on said frame,

a powered portable nailing gun removably attached to said bracket means, said gun including an actuating trigger, a nail supply means, a nail delivery tube means, and a surface-engaging safety trigger means for deactivating said gun when said nail delivery means is nonadjacent the surface to be nailed,

first relay means for actuating said trigger responsive to movement of said carriage over a surface to be nailed,

second relay means for actuating said trigger responsive to manipulation thereof by an operator independent of said first relays means.

coupling means for connecting said nailing gun and said relays to an external source of power.

2. The carriage of claim 1 wherein said third wheel has a small diameter relative to the diameter of said pair of wheels, said bracket means mounting said nailing gun to position the delivery means thereof laterally adjacent the forward end of said frame.

3. The carriage of claim 2 wherein said bracket means comprises:

an arm pivotally attached to said frame and extending upwardly therefrom,

a laterally extending flange connected to a free end of said arm, said flange having means thereon for removably fastening said portable nailing gun thereto,

spring means connected to said frame for counterbalancing said arm in an upward direction.

4. The carriage of claim 1 wherein said nailing gun is pneumatically powered, said coupling means comprising a first conduit means operatively coupled to said nailing gun at one end and terminating at its other end on said handle in means for connecting said first conduit means to an external source of pneumatic pressure, said first conduit means including a manifold from which pneumatic pressure is supplied to said first and second relay means.

5. The carriage of claim 4 wherein said first relay means comprises:

a pneumatic cylinder and piston mounted on said frame adjacent said nailing gun, said piston having an arm mounted adjacent said actuating trigger and having sufiicient travel to depress and release said actuating trigger,

a first pneumatic valve having a valve actuating arm with a cam follower attached thereto, said first valve means in fluid communication with said manifold,

second conduit means in fluid communication with said first pneumatic valve and said cylinder,

a cam means mounted for rotation with one of said pair of wheels for contacting said cam follower and moving said actuating arm at predetermined intervals,

said second relay means comprising:

a second pneumatic valve mounted on said carriage and having a hand-actuatable valve arm thereon,

third conduit means in fluid communication with said second pneumatic valve and said cylinder, said second pneumatic valve in fluid communication with said manifold.

6. The carriage of claim 1 further comprising:

shoe means capable of contacting a surface to be nailed and sliding therealong, said shoe means connected to said surface engaging safety trigger means, the height of said bracket being such that said safety trigger means will arm said gun when said wheels supporting said carriage are contacting a surface to be nailed and when said shoe means is contacting said surface to be nailed.

7. A carriage for use with a portable nailing gun having an actuating trigger thereon comprising:

a frame having supporting wheels journaled thereon, said frame including a handle for grasping by an operator,

a bracket means removably connectable to said portable nailing gun, said bracket means mounted for movement on said frame to recoil when said gun recoils and to allow said gun to return to a ready position after said recoil,

actuating means mounted on said carriage for operatively causing said gun to discharge a nail responsive to a signal from a relay means located elsewhere on said carriage.

8. The carriage of claim 7 further comprising:

a first relay means mounted on said frame and having an actuating bar associated therewith, said first relay means capable of transmitting a signal to actuate said actuating means,

cam means mounted to rotate with one of said wheels and associated with said actuating bar to actuate said relay means at predetermined intervals,

means for transmitting said signal from said first relay means to said actuating means.

9. The carriage of claim 7 further comprising:

a hand actuatable relay means mounted on said handle capable of transmitting a signal to actuate said actuating means,

means for transmitting said signal from said first relay means to said actuating means.

10. The carriage of claim 7 wherein said actuating means comprises a pneumatic piston and cylinder means associated with said trigger, said piston means movable to actuate said trigger responsive to said signal from said relay means, said relay means comprising a pneumatic valve means connectable to a source of pneumatic pressure, conduit means in fluid communication with said cylinder means and said valve means.

11. The carriage of claim 10 wherein said relay means further comprises:

a trip bar having a cam follower thereon and associated with a first pneumatic valve, said first pneumatic valve mounted on said frame,

cam means mounted for rotation with one of said wheels and for mating with said follower to trip said bar,

a first conduit in fluid communication between said first pneumatic valve and said pneumatic cylinder means.

12; The carriage of claim 10 wherein said relay means further comprises:

a second pneumatic valve mounted on said frame having a hand-manipulable actuating bar thereon,

a second conduit in fluid communication between said second pneumatic valve and said pneumatic cylinder means.

13. The carriage of claim 10 further comprising:

a third fluid conduit means having one end terminating in a coupling on said handle and having the other end terminating in a coupling adjacent said bracket, said third fluid conduit means for connecting said nailing gun to a remote source of fluid pressure, said third fluid conduit means having a manifold therein,

a fourth conduit means in fluid communication with said manifold and said valve means.

14. The carriage of claim 11 comprising:

a pair of wheels mounted on the rearward portion of said frame,

at least a third wheel mounted adjacent the forward portion of said frame, said third wheel having a small diameter relative to the diameter of each of said pair of wheels, said cam means comprising at least one cam roller mounted to rotate with one of said pair of wheels, said follower mounted in the path of rotation of said at least one cam roller on said wheel.

15. The carriage of claim 14 wherein said cam means further comprises a plurality of said cam rollers mounted equidistantly from the axis of rotation of said wheel, said plurality of rollers spaced at predetermined distances to periodically move said follower and actuate said first pneumatic valve.

16. Apparatus on which to support a normally handearried, trigger-operated fastener driver device while the device is propelled over a work surface and fasteners are driven into the surface from the device, comprising a carriage having spaced supportive surface engaging wheels on opposite sides thereof, whereby the carriage maintains a stable upright condition on the surface while it travels in one direction over the same, and a handle which is disposed adjacent the relatively rear end of the carriage in the direction of travel thereof, and is adapted to be grasped by an operator standing erect on the surface therebehind, means to support the driver device on the carriage in operative relationship to the surface, a fluid operated servo mechanism on the carriage for transmitting pressure pulses to the trigger of the driver device when the device is supported on the carriage, and valve means for actuating the servo mechanism.

17. The apparatus according to claim 16 wherein the servo mechanism includes a fluid operated piston device, and means for mounting the piston device in cooperative servo relationship with the trigger, and wherein the valve means is disposed on the carriage and is operative to transmit fluid pressure pulses to the piston of the piston device.

18. The apparatus according to claim 17 wherein the mounting means for the piston device is operative to mount the piston device on the driver device.

19. The apparatus according to claim 17 wherein the valve means include a cam operated valve in the servo mechanism, and cam means on one of the wheels operative to open or close the valve at predetermined angular intervals about the axis of the one wheel.

20. The apparatus according to claim 17 wherein the valve means include a manually operated control valve in the servo mechanism on the handle.

21. The apparatus according to claim 16 wherein the handle extends upwardly from the carriage and is rearwardly inclined to a point spaced relatively behind the carriage in the direction of travel thereof.

22. The apparatus according to claim 16 wherein the support means for the driver device include a bracket which is pivotally mounted on the carriage and attachable to the driver device to yieldably support the driver device in the operative condition thereof.

23. The apparatus according to claim 17 wherein the wheels are disposed at the rear end of the carriage, and there is a third wheel interposed therebetween at the forward end of the carriage, and a bracket pivotally interconnected with the carriage adjacent the third wheel, on which to suspend the driver device in outriggered condition on the carriage at one side thereof.

24. The apparatus according to claim 23 wherein there are cam means on one of the rear wheels, and a cam operated valve in the servo mechanism engageable by the cam means to operate the piston device at predetermined angular intervals about the axis of the one rear wheel.

25. The apparatus according to claim 24 wherein there is also a manually operated bypass valve in the servo mechanism on the handle.

26. In combination, a carriage having spaced supportive wheels on opposite sides thereof, in engagement with a surface therebelow, whereby the carriage maintains a stable upright. condition on the surface while it travels in one direction over the same, and a handle which is disposed adjacent the relatively rear end of the carriage in the direction of travel thereof, and is adapted to be grasped by an operator standing erect on the surface therebehind, a trigger operated fastener driver device mounted on the carriage so that fasteners can be driven into the surface from the carriage while the device is propelled over the surface thereon, a fluid operated servo mechanism on the carriage for actuating the trigger of the driver device while the device is propelled over the surface on the carriage, and valve means for actuating the servo mechanism.

27. The combination according to claim 26 wherein the servo mechanism includes a fluid operated piston device operatively interconnected with the trigger, and the valve means is operative to transmit fluid pressure pulses to the piston of the piston device.

Disclaimer 3,796,365.Hugh N. Downing, Marysville, Wash. NAILING GUN CAR- RIAGE. Patent dated Mar. 12, 1974;. Disclaimer filed Nov. 7, 1975, by the assignee, Glen D. Johnson. Hereby enters this disclaimer to claims 16 and 26 of said patent.

[Oyficz'al Gazette January 13, 1.976.] 

1. A nailing gun carriage comprising: a frame having forward and rearward ends, said frame including a handle affixed to the rearward end thereof, a pair of wheels journaled adjacent the rearward end of said frame, at least a third wheel journaled adjacent the forward end of said frame, bracket means mounted for upward and downward movement on said frame, a powered portable nailing gun removably attached to said bracket means, said gun including an actuating trigger, a nail supply means, a nail delivery tube means, and a surfaceengaging safety trigger means for deactivating said gun when said nail delivery means is nonadjacent the surface to be nailed, first relay means for actuating said trigger responsive to movement of said carriage over a surface to be nailed, second relay means for actuating said trigger responsive to manipulation thereof by an operator independent of said first relays means. coupling means for connecting said nailing gun and said relays tO an external source of power.
 2. The carriage of claim 1 wherein said third wheel has a small diameter relative to the diameter of said pair of wheels, said bracket means mounting said nailing gun to position the delivery means thereof laterally adjacent the forward end of said frame.
 3. The carriage of claim 2 wherein said bracket means comprises: an arm pivotally attached to said frame and extending upwardly therefrom, a laterally extending flange connected to a free end of said arm, said flange having means thereon for removably fastening said portable nailing gun thereto, spring means connected to said frame for counterbalancing said arm in an upward direction.
 4. The carriage of claim 1 wherein said nailing gun is pneumatically powered, said coupling means comprising a first conduit means operatively coupled to said nailing gun at one end and terminating at its other end on said handle in means for connecting said first conduit means to an external source of pneumatic pressure, said first conduit means including a manifold from which pneumatic pressure is supplied to said first and second relay means.
 5. The carriage of claim 4 wherein said first relay means comprises: a pneumatic cylinder and piston mounted on said frame adjacent said nailing gun, said piston having an arm mounted adjacent said actuating trigger and having sufficient travel to depress and release said actuating trigger, a first pneumatic valve having a valve actuating arm with a cam follower attached thereto, said first valve means in fluid communication with said manifold, second conduit means in fluid communication with said first pneumatic valve and said cylinder, a cam means mounted for rotation with one of said pair of wheels for contacting said cam follower and moving said actuating arm at predetermined intervals, said second relay means comprising: a second pneumatic valve mounted on said carriage and having a hand-actuatable valve arm thereon, third conduit means in fluid communication with said second pneumatic valve and said cylinder, said second pneumatic valve in fluid communication with said manifold.
 6. The carriage of claim 1 further comprising: shoe means capable of contacting a surface to be nailed and sliding therealong, said shoe means connected to said surface engaging safety trigger means, the height of said bracket being such that said safety trigger means will arm said gun when said wheels supporting said carriage are contacting a surface to be nailed and when said shoe means is contacting said surface to be nailed.
 7. A carriage for use with a portable nailing gun having an actuating trigger thereon comprising: a frame having supporting wheels journaled thereon, said frame including a handle for grasping by an operator, a bracket means removably connectable to said portable nailing gun, said bracket means mounted for movement on said frame to recoil when said gun recoils and to allow said gun to return to a ready position after said recoil, actuating means mounted on said carriage for operatively causing said gun to discharge a nail responsive to a signal from a relay means located elsewhere on said carriage.
 8. The carriage of claim 7 further comprising: a first relay means mounted on said frame and having an actuating bar associated therewith, said first relay means capable of transmitting a signal to actuate said actuating means, cam means mounted to rotate with one of said wheels and associated with said actuating bar to actuate said relay means at predetermined intervals, means for transmitting said signal from said first relay means to said actuating means.
 9. The carriage of claim 7 further comprising: a hand actuatable relay means mounted on said handle capable of transmitting a signal to actuate said actuating means, means for transmitting said signal from said first relay means to said actuating means.
 10. The carriage of claim 7 wherein said actuaTing means comprises a pneumatic piston and cylinder means associated with said trigger, said piston means movable to actuate said trigger responsive to said signal from said relay means, said relay means comprising a pneumatic valve means connectable to a source of pneumatic pressure, conduit means in fluid communication with said cylinder means and said valve means.
 11. The carriage of claim 10 wherein said relay means further comprises: a trip bar having a cam follower thereon and associated with a first pneumatic valve, said first pneumatic valve mounted on said frame, cam means mounted for rotation with one of said wheels and for mating with said follower to trip said bar, a first conduit in fluid communication between said first pneumatic valve and said pneumatic cylinder means.
 12. The carriage of claim 10 wherein said relay means further comprises: a second pneumatic valve mounted on said frame having a hand-manipulable actuating bar thereon, a second conduit in fluid communication between said second pneumatic valve and said pneumatic cylinder means.
 13. The carriage of claim 10 further comprising: a third fluid conduit means having one end terminating in a coupling on said handle and having the other end terminating in a coupling adjacent said bracket, said third fluid conduit means for connecting said nailing gun to a remote source of fluid pressure, said third fluid conduit means having a manifold therein, a fourth conduit means in fluid communication with said manifold and said valve means.
 14. The carriage of claim 11 comprising: a pair of wheels mounted on the rearward portion of said frame, at least a third wheel mounted adjacent the forward portion of said frame, said third wheel having a small diameter relative to the diameter of each of said pair of wheels, said cam means comprising at least one cam roller mounted to rotate with one of said pair of wheels, said follower mounted in the path of rotation of said at least one cam roller on said wheel.
 15. The carriage of claim 14 wherein said cam means further comprises a plurality of said cam rollers mounted equidistantly from the axis of rotation of said wheel, said plurality of rollers spaced at predetermined distances to periodically move said follower and actuate said first pneumatic valve.
 16. Apparatus on which to support a normally hand-carried, trigger-operated fastener driver device while the device is propelled over a work surface and fasteners are driven into the surface from the device, comprising a carriage having spaced supportive surface engaging wheels on opposite sides thereof, whereby the carriage maintains a stable upright condition on the surface while it travels in one direction over the same, and a handle which is disposed adjacent the relatively rear end of the carriage in the direction of travel thereof, and is adapted to be grasped by an operator standing erect on the surface therebehind, means to support the driver device on the carriage in operative relationship to the surface, a fluid operated servo mechanism on the carriage for transmitting pressure pulses to the trigger of the driver device when the device is supported on the carriage, and valve means for actuating the servo mechanism.
 17. The apparatus according to claim 16 wherein the servo mechanism includes a fluid operated piston device, and means for mounting the piston device in cooperative servo relationship with the trigger, and wherein the valve means is disposed on the carriage and is operative to transmit fluid pressure pulses to the piston of the piston device.
 18. The apparatus according to claim 17 wherein the mounting means for the piston device is operative to mount the piston device on the driver device.
 19. The apparatus according to claim 17 wherein the valve means include a cam operated valve in the servo mechanism, and cam means on one of the wheels operative to open or close the valve at predetermined angular intervals about the axis of the one wheel.
 20. The apparatus according to claim 17 wherein the valve means include a manually operated control valve in the servo mechanism on the handle.
 21. The apparatus according to claim 16 wherein the handle extends upwardly from the carriage and is rearwardly inclined to a point spaced relatively behind the carriage in the direction of travel thereof.
 22. The apparatus according to claim 16 wherein the support means for the driver device include a bracket which is pivotally mounted on the carriage and attachable to the driver device to yieldably support the driver device in the operative condition thereof.
 23. The apparatus according to claim 17 wherein the wheels are disposed at the rear end of the carriage, and there is a third wheel interposed therebetween at the forward end of the carriage, and a bracket pivotally interconnected with the carriage adjacent the third wheel, on which to suspend the driver device in outriggered condition on the carriage at one side thereof.
 24. The apparatus according to claim 23 wherein there are cam means on one of the rear wheels, and a cam operated valve in the servo mechanism engageable by the cam means to operate the piston device at predetermined angular intervals about the axis of the one rear wheel.
 25. The apparatus according to claim 24 wherein there is also a manually operated bypass valve in the servo mechanism on the handle.
 26. In combination, a carriage having spaced supportive wheels on opposite sides thereof, in engagement with a surface therebelow, whereby the carriage maintains a stable upright condition on the surface while it travels in one direction over the same, and a handle which is disposed adjacent the relatively rear end of the carriage in the direction of travel thereof, and is adapted to be grasped by an operator standing erect on the surface therebehind, a trigger operated fastener driver device mounted on the carriage so that fasteners can be driven into the surface from the carriage while the device is propelled over the surface thereon, a fluid operated servo mechanism on the carriage for actuating the trigger of the driver device while the device is propelled over the surface on the carriage, and valve means for actuating the servo mechanism.
 27. The combination according to claim 26 wherein the servo mechanism includes a fluid operated piston device operatively interconnected with the trigger, and the valve means is operative to transmit fluid pressure pulses to the piston of the piston device. 